Parasitic draw test

2003 Lincoln LS. I'm to do a PDT to try to find what is draining my battery. I'm going to charge the battery fully either with a charger or by driving it. I'll test the battery to be sure it's charged but my question is, how long does this car have to sit before it "goes to sleep"? I don't want to get any false readings on my multimeter. As always, thanks for your professional, and spot-on, advise.

Yes, anything aftermarket can and WILL cause issues. We see it on a daily basis with our fleet vehicles. Even something as simple as a cell phone charger left installed in a cigar lighter can do this. Not because it draws all that much power, but because it fools the battery saver relays, and keeps them from going to sleep. That in turn will power up a module when it shouldn't be.

And of course, battery saver relays have been known to stick. Or any other relay / module, CD changer, radio, door switches, etc.

Those are the types of repairs that will drive you nuts, and give you a reason to shop at your local liquor store.......

No longer working at dealerships. Government employee. Now i get paid to fix Fords.
ASE master tech
Private Pilot High Performance / Complex Rating.

The battery is dead late afternoon of the next day. If I start it in the morning it will start although it almost didn't start a couple days ago. I've had a trickle charge on last night and tonight. I won't have a chance to do the test until Friday or Saturday and I need to be sure it starts in the morning with no time to jump it.
I do have a dash cam but, suspecting it might be the cause, I disconnected it from the power source but the wire is still connected to the fuse. That didn't help.
I did have a cell phone charger connected but I saw the light on tonight and disconnected it. But it hasn't always been connected. Thanks for the help. I'll let you know what I find out in a couple of days.

Bill - How old is the battery? I chased my tail on a Grand Cherokee a year ago only to find out the battery itself was junk. I had charged it, disconnected both cables from the vehicle and the next day the battery was dead..... it had discharged itself.

Assuming the battery is newish, that's a considerable draw to take the battery down that quickly.

I'll imagine you checked that the trunk, glove box and other interior lights are shutting off? Also if you have lighted mirrors in the sun visors, make sure they're off?

I bought a battery recently thinking it was bad since it kept dying overnight. $100+ wasted; it wasn't the battery. Alternator was checked twice. Trunk and glove box lights are disconnected. Visors lights shut off. I have a lot going on tomorrow but I hope to do the PDT then.

The battery (Interstate) is new. Alternator is good. I disconnected the trunk light and glove box light (just because). Visor mirror light goes off on sides. I'll be busy tomorrow but I hope to have time to do the PDT.

When I do this test I need to check the inside fuse box. I need to know how to turn off the interior lights when the door is open to get an accurate reading on the multimeter. The door needs to stay open so I can get to the fuse box. I looked all around the door, and on the inside, but could not find a switch. I guess removing bulbs is an option but there has to be a better way. Thanks.